Re: Problems in Device Driver Development

["Tvrtko A. Uršulin" <tvrtko@croadria.com>]

> 1.   We are not able to use copy_to_user() a chunk of memory from 'write'
> function of the device driver. The pointer in the user space is passed to
> the kernel space through the 'ioctl' function of the device driver.

I am sure you get some return value from that function wich tells you what the 
problem is...

> 2.    We are not able to send a signal using kill_fasync() from within a
> kernel thread, to an user space process. The problem we face when we do
> this is that we get an OOPS message. I tried hard to decode this message,
> but in vain. So we came to the conclusion that i cannot send a signal from
> within the kernel thread using kill_fasync to a process that is running in
> the user space. Am i right in my conclusion, if not what should i do to
> make it possible.
>
> 3.   Similar to problem numbered 2, we face same problems in doing with
> 'tasklets'.

kill_fasync() works just fine if used properly.

Try to find Linux Device Drivers 2nd edition online book, it can explain this 
basic question to you.